The present invention relates to a voice output system and method, which is suitably applied, for example, to a home theater system.
Heretofore, in an Audio Video (AV) system, such as, for example, a home theater system, etc., a speaker is necessary to be connected to a device which acquires and outputs voice data of a tuner for television broadcasting, a Digital Versatile Disc (DVD) reproducer, etc.
In this case, for example, in the DVD standards, a 5.1 channel is defined as an audio channel. Further, as speakers, a total of six speakers or at least three front speakers, two rear speakers and one subwoofer are used. Thus, at least six speaker cables are needed to be wired. Such a wiring work is complicated. Also, many cables are drawn around from the reproducer and amplifiers, disfiguring the appearance after installation.
To solve the problems above, a technique is proposed and practically used, for example, as shown in FIG. 1, in a home theater 1 using a projector 2 as a video appliance, a DVD reproducer 3 is installed at a screen 4 side (hereinafter referred to as a “front side”). A voice signal and a video signal are transmitted to three front speakers 5A to 5C and a subwoofer 6 disposed at the front side and the projector 2 disposed at the side opposed to the video display surface of the screen 4 (hereinafter referred to as a “rear side”), from the DVD reproducer 3 through speaker cables 7A to 7D and a video cable 8. On the other hand, a voice signal is wirelessly transmitted by using an infrared ray and a radio wave to two rear speakers 9A and 9B arranged at the rear side.
However, with this technique, the DVD reproducer 3 is presupposed to be set at the front side. Therefore, there arises a necessity of drawing the video cable 8 for connecting between the DVD reproducer 3 and the projector 2 from the front side to the rear side. As a result, not only an appearance after the installation is disfigured, but also a video signal transmitted through the video cable 8 drawn from the front side to the rear side is deteriorated. Further, there also arises a problem that the quality of the display video is deteriorated.
Therefore, recently, a technique is proposed in which the DVD reproducer is disposed at the rear side, and the DVD reproducer and the projector are connected by a video voice cable. Further, the video voice data reproduced from a DVD output from the DVD reproducer is decoded in the projector and a video based on the acquired video data is projected on a screen by the projector. Then, the voice data of each channel acquired at this time is wirelessly transmitted from the projector to the corresponding speaker by using an infrared ray (for example, refer to Jpn. Pat. Appln. Laid-Open Publication No. 2003-188819).
With this technique, the wiring of the speaker cable from the DVD reproducer to each speaker can be made unnecessary. Further, the disfigurement of the appearance after the installation and the possibility of the deterioration of the quality of the display video can be prevented effectively.
However, with the technique above, the existing infrared wireless transmission system superposes voice data for two channels and transmits the voice data. Accordingly, the voice data for 5.1 channels (that is, 6 channels) must be divided for two channels and wirelessly transmitted. Therefore, there exist a plurality of carriers having different frequencies by superposing the different voice signals in the same space, causing a problem that the normal wireless transmission of the voice signal is difficult due to the interference of the carriers.
As the simplest technique for avoiding such interference, a technique is considered for superposing the voice data of two or more channels in the same carrier and wirelessly transmitting the voice data. However, in this system, as compared with the related technique which wirelessly transmits only the two channels, a wide bandwidth is necessary for the data transmission. As a result, there is a problem that the bandwidth overlaps with bandwidth used in other infrared wireless transmission systems, such as an infrared remote control system or the like, which adversely affect each other.